VS 2008 Passing ByRef Or ByVal?

Jul 23, 2010

I have been working on this for a few days, and I am going around in circles. I can make the program work by including everything in the same sub procedure, but the assignment requires that I do certain tasks by using function procedures.What I need to do is take the contents of a text box, reverse the order of the first and last names, and add them to a list box. I can do that, just not by passing value from a function procedure. Here is my

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VS 2008 Passing Parameters - ByVal/ByRef?

Dec 22, 2010

I have some code that is transforming the coordinates of a line.I want to keep the original coords and I thought passing the line ByVal would be the best way.The original VB6 code used a temporary variable so that the original coords were not updated.I'm confused as when the X & y coords of 'line' are changed 'MyLine' is also changed. I had assumed only 'line' would change and 'MyLine' would remain unchanged'.

Private Sub TransformSaveLine(ByVal MyLine As LineType)
Dim P As Integer
Dim line As LineType
Dim x As Double

[code].....

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ByRef Vs ByVal Performance When Passing Strings

Jul 22, 2010

Reading [URL] made me wonder whether the comments in there did apply to Strings in terms of performance. Since strings are copied before being passed, isn't it much more efficient (if the callee doesn't need a copy of string course) to pass strings ByRef?

[Code]...

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VS 2008 ByVal / ByRef List Parameter

Sep 4, 2010

I have a class OrderManager, that takes a parameter of type LocalFuturesList on construction. Now.. It doesn't seem to matter if I use ByRef or ByVal here.. It still references the parent class instance of it. It also doesn't seem to matter if I type New or omit it.. Probably also because it's just an address reference. But why is it like this? And what type of objects "acts" in this way? Further I find that if I change the object in the parent class by deserializing from a file (with my method call shown), then suddenly this reference is broken in some way, so the OrderManager instance now holds Nothing I believe.If my observations are correct I see two challenges:

1. How to pass a list NOT by reference?

2. How to maintain a list reference through deserialization? [code]

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When To Use ByVal And ByRef

Nov 17, 2011

I am a student and i get confused when i see a lot of ByRef and ByVal arguments in a sub procedure. Can someone make it simple for me to understand when it should be used?

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.net - ByRef Vs ByVal Clarification?

Dec 8, 2010

I've read a lot on this, but am having a hard time thinking through this tonight. (Maybe it's the hydrocodone... just had a root canal. i'm just starting on a class to handle client connections to a TCP server. Here is the code I've written thus far:

[Code]...

Now, on my Socket property, when setting the value, it is required to be ByVal. It is my understanding that the instance in memory is copied, and this new instance is passed to value, and my code sets _Socket to reference this instance in memory. Yes?

If this is true, then I can't see why I would want to use properties for anything but native types. I'd imagine there can be quite a performance hit if copying class instances with lots of members. Also, for this code in particular, I'd imagine a copied socket instance wouldn't really work, but I haven't tested it yet.

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Asp.net - .Net, EventArgs, ByRef And ByVal?

Dec 15, 2011

In VB.Net, I have an object named WorkflowButtonEventArgs that inherits from System.EventArgs.The WorkflowButtonEventArgs class contains two ByRef Properties. These are objects that are in memory, and I do not want them duplicated or copied in any way.

Can I pass the WorkflowButtonEventArgs object ByVal in VB.Net and have it still preserve the two ByRef definitions in WorkflowButtonEventArgs?Specifically, if I pass it ByVal:

Dim e As New WorkflowButtonEventArgs e has some ByRef properties RaiseEvent SomeEventName(e) ' e is passed ByVal Will the ByRef Properties/Members in e (WorkflowButtonEventArgs class) not be copied or duplicated in memory?

Long-story-short: Can I pass e ByVal, or do I need to pass it ByRef since it contains ByRef Properties?

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Difference Between Byref And ByVal

May 4, 2010

[Code] What is the difference between ByRef and Byval in this function. When i call this function and debug it it shows no difference the two. Can any one explain me actually what happens.

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Difference Between ByRef And ByVal?

Feb 20, 2009

ByRef (a.k.a. By Reference) points to where the object is in the memory. Any changes made to the object sent ByRef should change the values of the original object ByVal (a.k.a. By Value) points to a copy of the object. Any changes made to the object shouldn't change anything in the original object

Let's make an example:

Private Sub FormLoad()
Dim a As String = "A"
Dim b As String = "B"

[code]...

The second messagebox shows Baaaa - Buuuu instead of the expected A - Buuuu... but why is that? Apparently ByVal and ByRef does exactly the same thing. It seems like it sends the reference to the object when using ByVal, instead of making a new object.

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Difference Between ByVal And ByRef

Mar 27, 2012

Whenever I'm going to use a new API, I have to decide for each value whether I'm going to use byval or byref. Can someone explain me in what scenarios I should use which and why? Because lacking this knowledge kinda gives me the feeling of having no control over my code.I am aware about the other threads by people asking the same question, I have read them but its still not crystal clear for me.

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Difference Between ByVal And ByRef?

Jun 5, 2012

I have seen a few people in the past confused on the usage of ByRef & ByVal in a Function/Sub's Signature. I figured i would make a simple example that demonstrates the difference of each.

Option Strict On
Public Class Form1
Dim A As Integer = 100

[code]....

If you want something you've never had, you need to do something you've never done. If you believe something to be true, then one day you will be called upon to demonstrate that truth.

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Is Not Necesary To Indicate ByVal / ByRef Any More?

Feb 9, 2012

I just installed Visual Studio 2010 Service pack (proposed on Windows Update), and I can see a new feature on the "intellisense" that means when I write a Function or Sub in VB.NET it doesn't auto-complete parameters with ByRef or ByVal...

1) Is there anyway that I can configure this option back to how it was before?

2) If I don't specify ByX, which one is used by default? (it seems like it is always ByRef)

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What Is The Difference Between ByVal And ByRef

Apr 10, 2009

What is the difference between ByVal and ByRef? Please remember to mark the replies as answers if they help and unmark them if they provide no help.Welcome to the All-In-One Code Framework!

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ByRef Vs ByVal Generates Errors?

Apr 26, 2010

ByRef vs ByVal generates errors!?I had a method that used an Object Function Foo(ByRef bar as CustomObject) as Boolean this method generated errors, because some strange .NET Runtime things changed the bar object, causing its Dispose()al.A lot of time spent to understand the thing(where the ... object is changed), until somebody replaced ByRef by ByVal and object wasn't change anymore when passing to this method.As in my case the function Foo does NOT modify the bar, shouldn't ByRef or ByVal have the same effect?[code]

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Is The Return Expression ByRef Or ByVal

Jun 9, 2011

If a function returns a private shared (static) string, or a string declared as a module level variable, is the returned a reference to the shared string's instance or a different string instance having the same value?

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Function Return A Value Byref Instead Of The Default Byval?

Jan 18, 2012

Can a function return a value byref instead of the default byval? That is to say, allow me to directly edit the variable that it is retrieving instead of just giving me a copy of that variable.Right now I'm trying to write a function that will return, based on what the user has selected through a combobox, a particular setting (eg. My.Settings.somethingHere). I then want to be able to edit the setting directly through just calling the function. Is that at all possible?

[Code]...

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Functions Return Values As Byref Or Byval Or?

Oct 20, 2011

i have a strange issue today. Sample code is at the below of the post. The code that i have pointed out is too strange. According to my knowledge using return statement the functions return values as byval and copies the value to the stack. Also how can my class can reach outscope elements and change them. Take a look at to the code below. How this could be?

code
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim b As New ByteClass
Dim sumArray As Long = 0

[Code]...

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Pass ByRef And ByVal Parameters In Same Routine?

Dec 7, 2010

Is it considered bad practice (VB.NET or any language) to code a function with both ByVal and ByRef parameters as used in my getFile function below?

Function getFile(ByVal channel As Integer, _
ByRef Filename As String, _
ByRef Filesize As String) As Integer
End Function
Dim status As Integer

[Code]...

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Switching Byref To Byval On Method Calls .NET?

Mar 1, 2010

Switching Byref to Byval on method calls I have many warnings raised due to: "Implicit conversion from xxxx to yyyy in copying the value of 'ByRef' parameter zzzz back to the matching argument."

My feeling is that it would be safe to change the function parameters from byref to byval as nothing special is being done with the reference type pointers inside these methods the reference types are simply being used and I think the behaviour would be exactly the same if running with a copy a pointer rather than the original.

Another consideration is that I have two classes which inherit from a base class. The same situation is occuring in that the byref params are causing implicit casting from the base class to the narrower concrete class. Again I can't see any problems with this code running byval either.Does anyone have any tips regarding use of parameters in functions when dealing with reference types?

Some of the other things that are currently being passed around byref in my project are database connection objects i.e. OracleConnection and SqlConnection. Is there any good reason for passing these around byref?

[Code]...

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Limit To The Parameters That Can Be Passed ByVal Or ByRef To A Function ?

Jul 2, 2009

Is there a Limit to the parameters that can be passed byVal or byRef to a function or procedure in vb .net ?

[URL]

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VS 2005 Byref / Byval - Copy The Image Property To A Queue?

Jun 23, 2009

I have a 3rd party (c#) class that raises an event. on accsing this event i want to copy the image property to a queue.

Dim myQ as queue
Private Sub imageprocessor_NewImage() handles camera.NewImage
myQ.Enqueue(imageprocessor.currentimage)
End Sub

But when I view myQ at a later date it tells me the parameters of the images are not valid.Is it adding them by reference?i would have through adding an object to a queue was byval. how can i enforce this?

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ByRef & ByVal Code - Program To Execute Properly - Can't Get Them To Add Up And Display The Quantity And Price

Apr 7, 2010

I started this tutorial on sub procedures and am having trouble trying to get this program to execute properly. The problem lies with the total. I am trying to figure out the math part of it. When I hit F5 I can see this

Item Quantity Price.

Pizza Slices
Fries
Soft Drinks

Total

But I can't get them to add up and display the quantity and price. I tried the ByVal and ByRef code but am not sure if I did it right

Here is the code that I have so far:

Public Class Form1

Private Sub btnCompute_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCompute.Click

Dim pizza, fries, drinks, total As Double

[CODE]...

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What Are Classes , Objects , A Namespace , Subroutines,functions,methods,properties And Difference Between Byval And Byref

Jun 26, 2010

I want to know what are classes , objects , a namespace , subroutines,functions,methods,properties and differemce betweem byval and byref in your words.

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Force Passing Argument Byval?

Sep 16, 2010

I have an old unmanaged dll function and I want to pass an array to it.The dll function expects the array to be passed by reference.Sometimes I can do that and sometimes I need to pass a pointer in a variable.Is it possible to override the declare for the function so that I could pass either the array by ref, or a pointer to it if I need to?

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Passing Reference Types By Value (ByVal)

Aug 17, 2009

I'm still working on the code in this thread [URL] and as I mentioned in that thread, I thought that passing objects around between methods would probably be bad for performance (perhaps not really noticeably at first but maybe if I did it enough then it could have an impact).

1. When you pass a reference type to a method using ByVal then what is actually 'copied' ? I understand that ByVal copies the object into the local method that you are calling where as ByRef passes a reference to the actual object so you can work with the original object. So when you have a Reference type and you pass this ByVal then does copy the entire object or does it just copy a 'reference' to the object?

2. When working with an object that relates to a 'physical' item, such as a file on disk or a network stream between two connected machines, then what happens when you pass it around between methods (this might be irrelevant depending on the answer to the first question) ? I mean if I have a NetworkStream object that represents the data stream coming from a remote computer, if I then pass that ByVal into another method then does that mean I am still working with the same data stream or a copy of it or what?

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C# - .NET Interop Passing VB6 Form ByRef

Oct 11, 2011

I am trying to develop a .NET class that updates a VB6 Form and its controls with various new captions (It is in an assembly that is COM visible).

I pass a VB6 form ByRef as an object to the .NET class and then update the caption etc on the form as follows:

Public Sub AddFormRefLegacy(ByRef objForm As Object)
Try
objForm.Caption = "some new caption"

[Code].....

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VS 2010 Passing A Val ByRef To A Library?

Jan 31, 2012

I am trying to create a Library for like code that we use in more than one application. One call involves an array where I need to create a pointer to the array for what I need.

Is there a way to pass a value ByRef, have it increment, and return the value back to the original call?

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Original Value Changed While Passing Array Parameter Using ByVal?

May 31, 2009

have a subroutine which parameter is an array like below:

Private Sub DoubleArrayValues(ByVal arr() As Integer)
Double the values.

[code].....

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Passing String ByVal Into Function Without Changing Reference Value?

Jun 26, 2009

I know strings are immutable, so the minute you change a string reference's value .NET makes a brand new string on the heap. But what if you don't change the value of a string reference; rather, you simply pass it into a function ByVal -- does this operation copy the string value on the heap as well? My inclination is "no," but I'd like to confirm.

For example:
Public Function IsStringHello(ByVal test As String) As Boolean
Return (String.Compare(test, "Hello") = 0)
End Function

Calling program:
Dim myWord as String = "Blah"
Dim matchesHello as Boolean = IsStringHello(myWord)

I know passing myWord by value makes a copy of the reference to "Blah", but since I have not tried to change the string itself, would it make another copy of the string on the heap?

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C# - Interface Method Implementation And Passing ByRef?

Jan 9, 2010

I have a C# interface defined as so:

public interface IMenuSecurityService
{
void SetSecurityFlags(List<MenuItem> items);
}

I need to implement this interface in a VB.Net class. When I implement the SetSecurityFlags method with the items parameter passed ByVal, it compiles.

Public Sub SetSecurityFlags(ByVal items As List(Of L1.Common.Model.MenuItem)) Implements IMenuSecurityService.SetSecurityFlags
' do some work
End Sub

When I try to implement it with the items parameter passed ByRef, I get the following compiler error: Class 'UserRights' must implement 'Sub SetSecurityFlags(items As System.Collections.Generic.List(Of Model.MenuItem))' for interface

Public Sub SetSecurityFlags(ByRef items As List(Of L1.Common.Model.MenuItem)) Implements IMenuSecurityService.SetSecurityFlags
' do some work
End Sub

I can't seem to figure this one out. Does VB.Net not support this or am I doing something wrong?

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